Your Fallen London account is a StoryNexus account, so you can continue logging in through twitter to access that character. You may also link an e-mail to it so that you can simply type that in to log in. I don’t think you can connect it to your second Storynexus account, so you’ll just have to live with that. Maybe make a second Fallen London character to experience a different ambition? Or other things you won’t do on your main? Of course, all of this is assuming that I am not misunderstanding the heart of the issue.